Field of the Invention
The present invention relates to a thermostatic valve for a cooling system as well as a cooling system with a thermostatic valve, in particular for a motor vehicle.
Description of the Background Art
Thermostatic valves are known in the conventional art and are typically utilized in a cooling system of a liquid-cooled combustion engine, in particular a motor vehicle to control a coolant cycle with the objective to reach the optimal temperature in the combustion engine as soon as possible, to maintain it under all operating conditions and to prevent an overheating in the motor. This is of particular importance for the lifespan, fuel consumption and the development of exhaust fumes of the combustion engine. As a rule, the thermostatic valve is utilized as a 2/2 directional valve in the coolant cycle, if the engine temperature is too low after the start or if the pressure is too low during the driving of the motor vehicle. Due to the thermostatic valve the coolant streaming from the engine does not flow through a radiator of the coolant cycle, but immediately back to the engine via a bypass line.
Thermostatic valves, particularly thermostatic valves designed as 4/2 directional valves, are utilized as transmission fluid thermostats to regulate an oil temperature of a gear drive, for example automatic transmissions in the motor vehicle. The shifting ease can be especially improved for automatic transmissions, the wear of the gear drive can be reduced and a decrease of the temperature fluctuations of the transmission fluid can be achieved. This can result in a longer usability of the transmission fluid. Ultimately, fuel savings can be achieved in the popular driving cycles.
From the DE 10 2005 057 702 A1 a cooling arrangement is known with a thermostatic valve to monitor and/or adjust a coolant temperature. The cooling arrangement has a heat exchanger and a heat source with the heat source arranged in a coolant flow path as well as a bypass flow path to circumvent the heat exchanger. The thermostatic valve has a flow restrictor to control the volume flow of the coolant and a sensor to gauge the temperature of the coolant. The flow restrictor is for example designed as a disk valve or annular slide valve and is moveable as a function of the sensed temperature to clear a flow path to the heat exchanger.
The DE 10 2009 012 534 A1 shows a self-adjusting thermostatic valve to change a flow quantity of a fluid through a runner as a function of the temperature of the fluid. The thermostatic valve is arranged in a cooling system for a combustion engine. Here the flow quantity is automatically minimized when the fluid has a predetermined nominal temperature. The thermostatic valve also increases the flow quantity upon an increasing deviation from the nominal temperature, at which the flow quantity increases and decreases again approximately in proportion to the deviation from the nominal temperature, when the temperature of the fluid approaches the nominal temperature.
The DE 10 2011 114 308 A1 relates to a valve arrangement with at least two valves connected to a joint feeder line, wherein a first one of the valves is arranged as a return valve in a first line branching off of one of the feeder lines, and a second one of the valves as a thermally controlled thermostatic valve in a second line branching off of the feeder line. The return valve permits a flow only from the direction of the feeder line. It is so designed that a control element accessing the thermostatic valve is arranged in or at an intersection of the first line and the second line.